Modified Gas Turbine Engine Cuts Fuel Costs And Lowers Emissions

Source: William Lear, (352) 392-7572

GAINESVILLE, Fla. --- University of Florida engineers are hoping to save taxpayers money by making more efficient and earth-friendly gas turbine engines for naval vessels and tanks, as well as helicopters and small power plants.

William E. Lear, director of UF's Energy and Gasdynamic Systems Laboratory, said their gas turbine engine will feature a heat exchanger to reduce fuel costs and use a recirculating exhaust system to lower emission levels.

Researchers modified a gas turbine engine by adding a heat exchanger, a device similar to a car radiator, which extracts waste heat from the exhaust. Heating of the air in the exchanger means the engine needs less fuel to run, resulting in lower fuel costs.

In addition to adding the heat exchanger, a recirculating exhaust system was added to reuse exhaust air from the engine rather than releasing the contaminated air into the atmosphere. The exhaust system improves emission performance by running on about three parts recirculated exhaust to about one part fresh air.

Even with these additions, Lear said, the engine is small enough for a truck and powerful enough for a naval ship.

"As with other gas turbine engines, it is still compact," Lear said.

Lear said the main advantage is not the initial cost, but rather the lower operating costs and a compact design.

With the two additions, the engine runs more efficiently, he said. Current gas turbine engines are efficient at full power but rapidly lose efficiency as the engine speed drops and less air pressure is available to run the engine.

Lear said the new engine will run at its highest efficiency in 80 percent of its power range because the heat exchanger recovers wasted heat now released at low power levels.

Sponsors for the research project include NASA and the U.S. Army. Eventually, Lear said, the engine will be available commercially for electric power plants in a 30- to 100-kilowatt power range.

"The time scale is three to five years for implementation at a cost of several hundred million dollars for large engines," said Lear. "There is a couple years of more advanced development before [we get] the green light to use it commercially."